Protesters approach the Houses of Parliament during the London Climate March in November in London. (Chris Ratcliffe/Getty Images)

Regarding Robert J. Samuelson’s Dec. 28 op-ed, “Can we set the planet’s temperature?”:

Why haven’t our needed energy breakthroughs come soon enough to help us avoid the worst effects of climate change? There is simply no economic incentive for private investors to fund research and development in these technologies as long as fossil-fuel users are free to foul our atmosphere.

We could turn this situation around by applying a gradually increasing greenhouse-gas-emissions fee on fuel extractors and importers and returning all fee revenue to households equally. Prices for gasoline, fuel oil and natural gas would rise, providing an economic incentive for investors, entrepreneurs and businesses to invest in conservation, efficiency and renewable energy sources. Revenue returned to households would help consumers with rising energy costs during the transition to a clean-energy economy. A revenue-neutral greenhouse-gas fee would benefit jobs, the economy and health outcomes while dramatically reducing emissions.

Mr. Samuelson was correct: Fighting climate change requires more than soothing fantasies. It requires that we get the economics right.

Gary Rucinski, Newton, Mass.

The writer is Northeast regional coordinator for the Citizens’ Climate Lobby.

Robert J. Samuelson exuded a dangerous fatalism regarding climate change sadly similar to that which Republican presidential candidates are using to justify their irresponsible complaisance on the issue.

The United States is on course to meet its goal to cut emissions 17 percent below 2005 levels by 2020, despite congressional resistance and without significant economic costs, suggesting that the emissions pledges made in Paris are achievable. The prices of key technologies such as solar have fallen 80 percent in the past decade and are likely to get cheaper. Major economies such as China are deindustrializing and slowing coal use to improve air quality. Indeed, global carbon dioxide emissions fell slightly in 2015, in part because of these developments.

Mr. Samuelson was right that additional efforts will be needed, including tax incentives for carbon capture and storage technology.

Climate change is a difficult problem, but the United States has risen to such challenges before and seen our country and economy benefit. As President John F. Kennedy said, we embrace these challenges “not because they are easy, but because they are hard.” That’s what making America great again will require.

Paul Bledsoe, Arlington

The writer was communications director of the White House Climate Change Task Force under President Bill Clinton.

A carbon tax that addresses the economic externalities resulting in climate change will provide a powerful market signal not only for investment in renewable alternatives but also for overall energy efficiency and the development of other renewable alternatives not discussed in Robert J. Samuelson’s column. 

Such an approach would lessen the need for “choices” to be made by politicians and bureaucrats about what the “correct” energy mix should be. Most important, and in contrast with Mr. Samuelson’s pessimistic outlook, studies performed by economic forecasting firm Regional Economic Models and others quantitatively demonstrate that a gradually rising carbon tax would result in the reductions in greenhouse gases that scientists say must occur to avoid the most catastrophic outcomes of climate change.

Kyle E. Thomas, Syracuse, N.Y

Robert J. Samuelson said it is “a soothing fantasy” to believe the world can “wean itself from fossil fuels by substituting renewables.” This cynical thinking suggests humanity does not have the will and the decency to protect its children in the face of the high risks and high costs of global warming.

The potential for climate chaos and gutted economies is widely accepted by climate scientists and climate economists and increasingly accepted by the general population. As the effects of global warming become even more evident, people will demand that governments and corporations take the necessary actions to wean us off fossil fuels.

Many interventions are in place, such as the Clean Power Plan, the U.N. Green Climate Fund, the Breakthrough Energy Coalition and the U.S.-China agreement on carbon emissions. And many interventions will be implemented to limit global warming, including mandated building and transportation energy efficiency, a price on carbon pollution, elimination of fossil-fuel subsidies, preferential tax treatment and financing for clean energy, use of hydroelectric power and geothermal electricity generation.

Limiting global warming is a mission possible because humanity will demand it.  

James Little, Seattle